Changes in Ecosystems:.

Ecological Succession

• Do all ecosystems stay the same all the time?

• What are some things that cause changes to ecosystems?–Natural and unnatural (Quickly and

slowly)

Ecological succession

• DEFINITION:

• Series of predictable changes that occur in a community over time. Caused by:– Physical environment– Natural disturbance– Human disturbance

Primary Succession

• Begins in a place without any soil – Sides of volcanoes

– Landslides

– Glacier melting

• Starts with the arrival of living things such as lichens that do not need soil to survive, called PIONEER SPECIES.

Pioneer species

http://www.life.uiuc.edu

http://uisstc.georgetown.edu

http://www.uncw.edu

Primary Succession

Reaching a mature community can

take CENTURIES.

Secondary Succession

• It´s the series of changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist.

• Succession following a disturbance that destroys a community without destroying the soil

• Natural Human disturbance– Hurricane - Farming– Fires - Forest clearing

Secondary succession

• Unlike primary succession, secondary succession occurs in a place where and ecosystem currently exists.

• And occurs more rapidly than primary succession.

http://www.geo.arizona.edu

http://www.ux1.eiu.edu

References:

• http://www.slideshare.net/radhakrishnan1962/ecological-succession-1

• Science explorer Prentice Hall. Environmental Science

CLASSWORK

• PAGE 35